The present invention relates generally to agricultural combine rotors, and more particularly, to a front bearing housing and rotor front inlet section combination having anti-wind geometry for preventing winding or wrapping of plant materials therearound.
A well-known form of harvesting machine is a rotary combine. A typical combine includes a crop harvesting apparatus which reaps grain stalks and other plant materials and feed them to a separating or threshing apparatus. The grain stalks or other crop and plant materials harvested in the field are moved rearwardly from a crop harvesting header assembly and introduced for threshing to the rotor assembly by a crop feeder assembly.
In a rotary combine, the rotor assembly includes a generally tubular rotor housing mounted in the combine body. A driven rotor is coaxially mounted within the housing. The rotor comprises an infeed or inlet section and a cylindrical threshing section, and is supported at opposite ends by front and rear bearing assemblies.
The cylindrical threshing section of the rotor and the rotor housing mount cooperating threshing elements which separate grain from other material in a threshing zone. The crop material is threshed as it spirals around the rotor threshing section and passes through openings in the rotor housing.
As discussed in Tanis U.S. Pat. No. 5,387,153, assigned to the same assignee as the present invention, the ability to transfer crop materials from the feeder assembly to the threshing zone of the rotor assembly is a key to efficient combine operations. Most rotary combine rotors include an infeed or inlet section impeller comprised of a series of impeller blades or flights arranged at a forward end of the rotor. The impeller flights rotate within a housing which is a part of the rotor housing. During harvesting operations, the generally linear movement of the crop materials received from the feeder assembly is converted by the rotating impeller flights into a rotating, circulatory movement, in a rearward and outward direction.
When rotary combines are used on certain long-stemmed leguminous or grassy crops, such as windrowed perennial or annual rye grass, clover, and bent grass, there is a potential for portions of such grassy crops and other plant materials such as weeds to extend into the impeller flights while other portions remain partially engaged with the feeder assembly. The latter portions tend to move toward the axis of rotation of the rotor assembly, and may wrap about the front rotor bearing or shaft.
Long-stemmed leguminous or grassy crops also have a tendency to wrap around or xe2x80x9chairpinxe2x80x9d about the leading edge of the impeller blades or flights. This hairpinning action can create a buildup of crop materials on the aforementioned leading edge, which reduces the effectiveness of the impeller and further reduces combine efficiency.
Numerous impeller designs, including that disclosed in the above referenced Tanis patent, have been proposed to prevent crop materials from becoming entangled with the front rotor bearing and prevent hairpinning about the impeller blades, leading edges. None has been thoroughly successful in doing so, however. Furthermore, these designs suffer from a multitude of individual parts, and the higher costs associated therewith.
Tanis U.S. Pat. No. 6,296,566, also assigned to the same assignee as the present invention, discloses an infeed impeller for a rotary combine which utilizes anti-winding vanes on the rotor which cooperate with vanes on the front bearing assembly to force debris radially outwardly away from the axis of the rotor. However, this combination has been found to also suffer from shortcomings, namely, that long, particularly wet, crop material winds onto the rotor shaft which creates heat, consumes power, and causes early bearing failures.
Accordingly, what is sought is a front bearing housing and rotor auger inlet impeller flight combination which provides improved anti-wind characteristics, particularly with regard to long, wet straw.
According to the invention, a threshing rotor and front bearing housing shroud assembly for an agricultural combine having improved anti-wind characteristics, particularly with regard to long, wet straw, is disclosed. The invention includes a front rotor inlet or infeed section having a front center portion, the front rotor inlet section being rotatable with the rotor in a predetermined rotational direction about an axis extending through the front center portion, the front center portion including a radial outer circumferential edge portion having a predetermined radial extent, and at least one impeller or auger flight having a front leading edge extending radially outwardly from the front center portion so as to be swept back relative to the predetermined rotational direction. The invention includes a front bearing housing positionable in front of the front rotor inlet section in rotatable connection with and in closely spaced opposing relation to the front center portion for supporting the front rotor inlet section for rotation about the axis, the front bearing housing including a radial outer circumferential surface having a predetermined radial extent. A shroud extends at least partially circumferentially around the front bearing housing, the shroud having a radial inner circumferential surface having a predetermined redial extent which is greater than the radial extent of the front bearing housing such that a generally annular space is disposed therebetween, and also greater than the radial extent of the front center portion so as to be located at least slightly radially outwardly thereof, the shroud including a radially outwardly facing curved anti-wind wiper surface extending tangentially and radially outwardly therefrom in the predetermined direction of rotation and in position such that when the front rotor inlet section is supported by the front bearing housing and rotated relative thereto in the predetermined rotational direction, the front leading edge of the impeller will rotate in closely spaced axially opposing relation to the anti-wind wiper and will always form at least a 90xc2x0 angle thereto so as to urge plant material coming into contact therewith radially outwardly away from the front bearing housing. And, the front center portion of the front rotor inlet section includes at least one frontwardly extending lug positioned so as to project into and rotate through the space between the radial inner circumferential surface of the shroud and the radial outer circumferential surface of the bearing housing as the front rotor inlet section rotates relative thereto for agitating material that enters the space and directing the material radially outwardly therefrom.
Preferably, the at least one lug has a surface which faces the predetermined rotational direction and is swept back relative thereto, and the shroud can include one or more openings therethrough oriented in the rotational direction for the passage of material directed by the at least one lug from the space therethrough. The front bearing housing or the shroud can also include one or more edges located in the space in position such that the at least one lug will pass thereby in closely spaced relation thereto to facilitate the agitation.
Also preferably, the front center portion includes at least one radially outwardly extending anti-wind flight on the radial outer circumferential edge portion for contacting material disposed between the front center portion and the shroud and urging the material radially outwardly therefrom, the anti-wind flight preferably including a surface facing the predetermined rotational direction which is raked or oriented radially outwardly and rearwardly for urging material that comes in contact therewith in the radial outward and rearward direction.
The anti-wind swept back geometry of the inlet impeller or auger flights in combination with the shroud geometry operate to urge or move long, wet grasses and other troublesome plant material radially outwardly away from the front bearing and shaft supporting the front inlet end of the rotor, while the raked back anti-wind flights drive material that gets close to the front center portion radially outwardly and rearwardly, and the swept back internal lugs moving through the space between the shroud and bearing housing agitate and direct outwardly material which reaches that region, such that a comprehensive anti-winding and wrapping capability is effected.